schneeland
Hero
I bought Art & Arcana in 2018. If we only talk about source books, it was probably Xanathar's Guide in 2017. Admittedly, I did use Tasha's Cauldron (from 2020), but there I used a friend's copy and didn't buy it myself.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.